President Barack Obama and Yemen’s president, Abed Rabbo Mansour Hadi, pledged Thursday to work together to repatriate dozens of Guantanamo Bay detainees to the country.

But while Obama praised Hadi for his country’s efforts battling terrorism, there was no pledge that any Yemeni detainees would be transferred soon to their homeland.

What to do about the dozens of Yemenis held at Guantanamo is one of Obama’s biggest challenges in delivering on a failed first-term campaign promise to close the controversial detention center. More than half of the 166 detainees still at the prison are Yemeni, including 56 of the 86 detainees who already have been declared eligible for transfer or release.

Neither man mentioned the detention center as they appeared before cameras in the Oval Office, but a joint statement released after the event said they “agreed to cooperate closely to enable the return of Yemeni detainees at Guantanamo Bay who have been designated for transfer.”

Obama in May lifted a moratorium on repatriations to Yemen he had imposed after the 2009 Christmas Day attempt to bomb an aircraft as it was landing in Detroit after a flight from Amsterdam.

White House Press Secretary Jay Carney said before the meeting that the lifting of the moratorium wouldn’t create a “mass exodus” but would mean a “case-by-case evaluation of each detainee.”

U.S. officials have been reluctant to certify Yemenis for transfer home because al Qaida in the Arabian Peninsula remains active there. That apparently remained a worry at Thursday’s meeting; the joint statement said that Hadi had “affirmed his intention to establish an extremist rehabilitation program to address the problem of violent extremism within Yemen, which could also facilitate the transfer of Yemeni detainees.”

The two presidents agreed to remain in “close consultation on this critical matter,” the statement said.

Obama credited Hadi for cooperation on counterterrorism efforts, saying that because of military reforms that Hadi initiated, “what we’ve seen is al Qaida in the Arabian Peninsula, or AQAP, move back out of territories that it was controlling.”

Hadi said counterterrorism efforts against al Qaida were critical to Yemeni interests, as well, because the threat of al Qaida had shut down the country’s tourism and oil industries.

“Our cooperation against those terrorist elements are actually serving the interests of Yemen,” he said through a translator.

In the joint statement, the two said the countries would continue working together to expand economic opportunities and foster private-sector development in the impoverished nation.

While in the U.S., Hadi said, he’d met with the International Monetary Fund and World Bank. Both presidents “urged donors to continue supporting Yemen as it addresses a serious humanitarian crisis and begins fulfilling its commitments to responsible governance and reform.”